Genetic researchers are beginning the large-scale investigation of the function of mammalian genome. Genetically-defined and genetically- engineered mice are the mammalian model of choice for this research by virtue of their extensively analyzed genome and the availability of methods for sophisticated genetic manipulations. The Jackson Laboratory (TJL) is a national resource for the development, analysis, and distribution of laboratory mice and information about them. Research programs conduct independent, hypothesis-driven research that leads to the development and characterization of new models. Resource programs are directed by scientific staff members and develop, characterize, maintain, and distribute mouse models for research. A growing Bioinformatics program is the national resource for genetic, phenotypic, expression, and comparative data on the mouse, including data generated within and outside TJL. The project described in this application will provide facilities to expand TJL's capacity for the development, characterization, and dissemination of mouse models for human diseases. The proposed facilities will: a) house the animal colonies for large-scale mutagenesis program to generate new mutants for TJL staff and the wider scientific community; b) expand our capabilities to screen mutant stocks and inbred strains for an array of phenotypes relevant to major human diseases; and c) provide training facilities for workshops on mouse model development and characterization.